Network,Time,Protocol,NTP,The, computer Network Time Protocol (NTP): The Way it Works
----------------------------------------------------------Permission is granted for the below article to forward,reprint, distribute, use for ezine, newsletter, website,offer as free bonus or part of a product for sale as longas no changes a Gone are those times when the companies and the organisations didn't need a hi-tech system to handle them. Owing to the considerable increase in the business sector and thus, an enormous increase in the complexity of the organisational struc
Network TimeProtocol (NTP) is probably the Internets oldest protocol. Developed at theUniversity of Delaware, it has been in use and continually updated for the last25 years. In short it is a protocol designed to synchronize the clocks oncomputers and networks across the Internet or Local or Wider Area Networks(LANs/WANS).NTP is a multi-tieredsystem, each tier being called a stratum. Servers at each tier communicate witheach other (peer) and provide time to lower strata. Servers at the top stratum,stratum 1 connect to an atomic clock either over the Internet or by a radio orGPS receiver while a stratum 2 server will connect to a stratum 1.The way NTPworks is relatively straight forward. NTP timestamps relaythe seconds from a set point in time (known as the prime epoch, usually set at00:00 1 January 1900 or sometimes 00:00 1 January 1970) The NTP algorithm then determines the amount toadvance or retreat the clock. The NTP program (known as a daemon on UNIX and aservice on Windows) runs in the background and refuses to believe the time itis told until several exchanges have taken place, each passing a set of tests.If the replies from a server satisfy these protocol specifications, theserver is accepted. It usually takes about five good samples (five minutes)until a NTP server is accepted as a source forsynchronisation. NTP can synchronise time over the Internet but it should benoted that Microsoft and others recommend that external time references areused rather than Internet based ones as these cant be authenticated. External hardware sources use either a radioor GPS receiver to get a timing reference from an atomic clock.NTP (currently up to version 4) can maintain timeover the Internet to within 1/100th of a second (10 milliseconds ()and can perform even better over Local Area Networks with accuracies of 1/5000thof a second (200 microseconds) fairlycommon.A simplified version of NTP called Simple NetworkTime Protocol (SNTP) exists that does not require the storing of informationabout previous communications as required by NTP. It is used in some devicesand applications where high accuracy timing is not as important and isinstalled on older versions of Microsoft Windows.Windows since 2000 has included the Windows Time Service (w32time.exe) whichuses SNTP to synchronisethe computer clock. NTP is also available on UNIX and LINUX (download viaNTP.org).
Network,Time,Protocol,NTP,The,